Professor, retired

Research

Neuromodulatory and sensory-motor networks in insects

Active locomotion is a feature of all animals, and to achieve this animals have developed (i) muscles which are innervated by excitatory motor neurones, inhibitory neurones and neuromodulatory neurones, (ii) sensory receptors that monitor the effects of movements, ...

Tyramine is a precursor of octopamine and an independent transmitter.

Recently we used antibodies against tyramine and octopamine to label the distribution of the respective neurones in the brain and all segmental ganglia, We found pure tyraminergic neurones predominantly in the brain, and a relative small number in fused segmental ganglia.

Connectivity of octopaminergic DUM and VUM neurons

A remaining unanswered question is that of the connectivity of these neurones. Although we know that DUM/VUM neurones are always activated or inhibited in parallel to motor neurones some important differences exist: (i) the connections of known descending interneurones are ...

Ultrastructure of neuromodulatory terminals

This project tries to reveal the ultrastructure of neuromodulatory terminals on target muscles. Normal motor terminals are of type I morphology (in Drosophila terminology), and neuromodulatory terminals are of type II. From an evolutionary point of view the latter type II ...

According to our results octopaminergic DUM/VUM neurones are divided into subpopulations that are specifically recruited (activated or inhibited) during motor behavior, that behave very differently to sensory stimulation and that also exhibit different electrical properties.

Development of sensory hairs and their first order interneuron

We also examine the postembryonic changes of a sensory-motor circuit in locusts which is used for flight steering in the adult animal. Detailed studies are concerned with the organisation of the receptive field of an identified ventral cord interneurone (A4I1), and how hormones and ...

Evolution

Last but not least, we are interested in the behavioural function of identified circuits which may change during development of hemi- or holometabolous insects and during evolution. They may be very conserved in different species, or they may have undergone interesting adaptive ...